04/16/2010 AT 4:35 PM ET
Could Pink and hubby Carey Hart be expanding their family?
After a picture surfaced of the singer appearing to have a slight baby bump earlier this week, blogs began buzzing about whether Pink’s pregnant.
So far, she s not saying, but she Tweeted about the speculation. “Off to the gym,” she wrote on Twitter Thursday. “Lord knows when this 600-lb baby comes out that I’ve been growing for 8 years, i better be strong and physically prepared!!!”